Usually my projects are machines, functional parts such as tools and/or nice to have gimmicks, but only rarely for aesthetic reasons. Moreover, I then rarely find these projects interesting enough to write something about them, so most of them never get documented. But this one is different. Mainly, because it is the single most complicated part that I ever designed. Why? Because I just didn’t want to be left defeated by a … pine cone. Well yes. I spend way more time than I thought designing something that trees produce in masses.
The why is easy enough. On and off, I am working on my wall plotter project and this time around, I was fed up with the counter weights that I put on the belt tighteners. For more than two years now, I have had two plastic bottles filled with water hanging in my workroom and from day one I did not like the look of it. I always thought I would replace them sooner than later with something nice. But time went by and I just lived with the temporary solution. Then I moved, so I packed everything up (Yes, also those water bottles) and started putting everything back together again. And I really hated to put the bottles back up again. So I opened ebay Kleinanzeigen and I started looking for clock weights. I always wanted some, but they felt just too expensive as a simple counter weight. I got lucky enough and the same day, I bought a pair of used clock weights for a few Euros.
But they were too heavy.
I was super annoyed that the nice looking weights are basically useless to me. The problem was that by chance, the water bottles had the exact weight that when powered off, the motors would neither spin forward nor backwards, without any additional breaks installed. This was super handy for long prints where I needed or wanted to power the bot down.
Before buying another set of weights I figured that I wanted an adjustable solution, which I could make heavier or lighter depending on my needs. And since I love modeling stuff up on my computer, I started drawing shapes that I could 3D print and use as weight.
After a few hours, I knew I wanted a pine cone. I knew it should be hollow so I can fill it up with weights and I knew it should be adjustable (without a weight permanently enclosed in the print). But modeling such a shape up in CAD is really difficult. So I turned to my old love Blender and got there super quick. But in fact, with so many intersecting pieces, it was impossible to get the shape water tight (no open faces). And this is a basic requirement. Also I struggled to put 3D printable threads inside such that I could open and close the cone. So back to Fusion 360. After several restarts from scratch and almost one entire day of work, I was finally there.
A pine cone.
It looked marvelous and is super easy to print. Only two parts, minimal preparation and minimal clean up after print. The threads work nicely and the weight I needed could be easily achieved with spare coins I had waiting in a jar.
I also tried smaller versions at 75% scale & 50% scale to see if the clearances for the threads would work and they do.
The file is now als available on Cults3D for purchase for 1.49€
So if you have an inquiry for an intriguing shape that needs to remain 3D printable, feel free to write to me about it.
